1. Field of the Invention
The present invention relates to an inorganic board suitable for building boards, and to a method of manufacturing of the inorganic board.
2. Description of the Related Art
Compositions that comprise an aluminosilicate setting material and an aggregate, as starting materials, are known in the art. For instance, Japanese Patent Application Publication No. 2008-239446 discloses a composition comprising fly ash, an alkaline activator, and an aggregate and discloses a method of manufacturing the composition. The described composition can be used in construction, civil engineering and structure formation.
However, the composition disclosed in Japanese Patent Application Publication No. 2008-239446 has high specific gravity and small deflection, and hence is not suitable for use in building boards. A fibrous reinforcing material is required in order to lower the specific gravity and improve deflection. However, synthetic fibers are expensive, and contribute little to lowering the specific gravity. By contrast, wooden reinforcing materials are inexpensive and are suited for lowering specific gravity.
When producing a composition through addition of a wooden reinforcing material, however, problems arise in that, after setting, colored materials that come into contact with water leach into the latter, giving rise to contamination. This is deemed to arise from extraction of lignin and other components from wood as a result of contact between the wooden reinforcing material and the alkaline activator. The extracted components leach thereupon to the surface of the composition. In consequence, it is difficult to use a composition containing an aluminosilicate setting material and a wooden reinforcing material in building boards, for instance outer siding boards that are exposed to rain and the like, and inner wall boards where contact with water might be likely.